Optical system, optical apparatus and method for manufacturing the optical system

ABSTRACT

An optical system (LS) has a lens (L11) that satisfies the following conditional expressions.−0.010&lt;ndLZ−(2.015−0.0068×νdLZ)50.00&lt;νdLZ&lt;65.00 0.545&lt;θgFLZ−0.010&lt;θgFLZ−(0.6418−0.00168×νdLZ)where ndLZ is the refractive index to the d line of the lens, νdLZ is the Abbe number with respect to the d line of the lens, and θgFLZ is the partial dispersion ratio of the lens.

TECHNICAL FIELD

The present invention relates to an optical system, an optical apparatus and a method for manufacturing the optical system.

TECHNICAL BACKGROUND

In recent years, the image resolutions of imaging elements included in imaging apparatuses, such as digital cameras and video cameras, have been improved. It is desired that a photographing lens provided in an imaging apparatus including such an imaging element be a lens of which not only the reference aberrations (aberrations for single-wavelength aberrations), such as the spherical aberration and the coma aberration, be favorably corrected, but also chromatic aberrations be favorably corrected so as not to cause color bleeding for a white light source, and which have a high resolution. In particular, for correction of the chromatic aberrations, it is desirable that not only primary achromatism be achieved but also secondary spectrum be favorably corrected. As means for correcting the chromatic aberrations, for example, a method of using a resin material having anomalous dispersion characteristics (for example, see Patent literature 1) has been known. As described above, accompanied by the recent improvement in imaging element resolution, a photographing lens with various aberrations being favorably corrected has been desired.

PRIOR ARTS LIST Patent Document

-   Patent literature 1: Japanese Laid-Open Patent Publication No.     2016-194609(A)

SUMMARY OF THE INVENTION

An optical system according to the present invention comprises a lens, the lens satisfying the following conditional expressions:

−0.010<ndLZ−(2.015−0.0068×νdLZ),

50.00<νdLZ<65.00,

0.545<θgFLZ,

−0.010<θgFLZ−(0.6418−0.00168×νdLZ)

where ndLZ: a refractive index of the lens for d-line,

νdLZ: an Abbe number of the lens with reference to d-line, and

θgFLZ: a partial dispersion ratio of the lens, defined by a following expression when a refractive index of the lens for g-line is ngLZ, a refractive index of the lens for F-line is nFLZ, and a refractive index of the lens for C-line is nCLZ:

θgFLZ=(ngLZ−nFLZ)/(nFLZ−nCLZ).

An optical apparatus according to the present invention comprises the optical system described above.

A method for manufacturing an optical system according to the present invention arranges each lens in a lens barrel so that the optical system comprises a lens that satisfies the following conditional expressions:

−0.010<ndLZ−(2.015−0.0068×νdLZ),

50.00<νdLZ<65.00,

0.545<θgFLZ,

−0.010<θgFLZ−(0.6418−0.00168×νdLZ)

where ndLZ: a refractive index of the lens for d-line,

νdLZ: an Abbe number of the lens with reference to d-line, and

θgFLZ: a partial dispersion ratio of the lens, defined by a following expression when a refractive index of the lens for g-line is ngLZ, a refractive index of the lens for F-line is nFLZ, and a refractive index of the lens for C-line is nCLZ:

θgFLZ=(ngLZ−nFLZ)/(nFLZ−nCLZ).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to First Example;

FIGS. 2A, 2B and 2C are graphs respectively showing various aberrations of the optical system according to First Example upon focusing on infinity, upon focusing on an intermediate distant object and upon focusing on a short distant object;

FIG. 3 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Second Example;

FIGS. 4A, 4B and 4C are graphs respectively showing various aberrations of the optical system according to Second Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 5 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Third Example;

FIGS. 6A, 6B and 6C are graphs respectively showing various aberrations of the optical system according to Third Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 7 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Fourth Example;

FIGS. 8A, 8B and 8C are graphs respectively showing various aberrations of the optical system according to Fourth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 9 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Fifth Example;

FIGS. 10A, 10B and 10C are graphs respectively showing various aberrations of the optical system according to Fifth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 11 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Sixth Example;

FIGS. 12A, 12B and 12C are graphs respectively showing various aberrations of the optical system according to Sixth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 13 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Seventh Example;

FIGS. 14A, 14B and 14C are graphs respectively showing various aberrations of the optical system according to Seventh Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 15 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Eighth Example;

FIGS. 16A, 16B and 16C are graphs respectively showing various aberrations of the optical system according to Eighth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 17 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Ninth Example;

FIGS. 18A, 18B and 18C are graphs respectively showing various aberrations of the optical system according to Ninth Example upon focusing on infinity in the wide-angle end state, the intermediate focal length state and the telephoto end state;

FIG. 19 is a lens configuration diagram of an optical system in a state upon focusing on infinity according to Tenth Example;

FIGS. 20A, 20B and 20C are graphs respectively showing various aberrations of the optical system according to Tenth Example upon focusing on infinity, upon focusing on an intermediate distant object and upon focusing on a short distant object;

FIG. 21 shows a configuration of a camera that includes the optical system according to this embodiment; and

FIG. 22 is a flowchart showing a method of manufacturing the optical system according to this embodiment.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, preferable embodiments according to the present invention are described. First, a camera (optical apparatus) that includes an optical system according to this embodiment is described with reference to FIG. 21. As shown in FIG. 21, the camera 1 is a digital camera that includes the optical system according to this embodiment, as a photographing lens 2. In the camera 1, light from an object (photographic subject), not shown, is collected by the photographing lens 2, and reaches an imaging element 3. Accordingly, the light from the photographic subject is captured by the imaging element 3, and is recorded as a photographic subject image in a memory, not shown. As described above, a photographer can take the image of the photographic subject through the camera 1. Note that this camera may be a mirrorless camera, or a single-lens reflex camera that includes a quick return mirror.

As shown in FIG. 1, an optical system LS(1) as an example of the optical system (photographing lens) LS according to this embodiment comprises a lens (L11) that satisfies the following conditional expressions (1) to (4). In this embodiment, for discrimination from the other lenses, the lens that satisfies the conditional expressions (1) to (4) is sometimes called as a specified lens.

−0.010<ndLZ−(2.015−0.0068×νdLZ)  (1),

50.00<νdLZ<65.00  (2),

0.545<θgFLZ  (3),

−0.010<θgFLZ−(0.6418−0.00168×νdLZ)  (4)

where ndLZ: a refractive index of the specified lens for d-line,

νdLZ: an Abbe number of the specified lens with reference to d-line, and

θgFLZ: a partial dispersion ratio of the specified lens, defined by a following expression when a refractive index of the specified lens for g-line is ngLZ, a refractive index of the specified lens for F-line is nFLZ, and a refractive index of the specified lens for C-line is nCLZ:

θgFLZ=(ngLZ−nFLZ)/(nFLZ−nCLZ).

Note that the Abbe number νdLZ of the specified lens with reference to d-line is defined by the following expression:

νdLZ=(ndLZ−1)/(nFLZ−nCLZ).

According to this embodiment, the optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected, and the optical apparatus that includes this optical system can be achieved. The optical system LS according to this embodiment may be an optical system LS(2) shown in FIG. 3, an optical system LS(3) shown in FIG. 5, an optical system LS(4) shown in FIG. 7, an optical system LS(5) shown in FIG. 9, or an optical system LS(6) shown in FIG. 11. The optical system LS according to this embodiment may be an optical system LS(7) shown in FIG. 13, an optical system LS(8) shown in FIG. 15, an optical system LS(9) shown in FIG. 17, or an optical system LS(10) shown in FIG. 19.

The conditional expression (1) defines an appropriate relationship between the refractive index of the specified lens for d-line and the Abbe number with reference to d-line. By satisfying the conditional expression (1), correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration can be favorably performed.

If the corresponding value of the conditional expression (1) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (1) to −0.005, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (1) may be set to −0.001, 0.000, 0.003, 0.005 or 0.007, or further to 0.008.

Note that the upper limit value of the conditional expression (1) may be set to less than 0.150. Accordingly, correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed. In this case, by setting the upper limit value of the conditional expression (1) to 0.100, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (1) may be set to 0.080, 0.060 or 0.050, or further to 0.045.

The conditional expression (2) defines an appropriate range of the Abbe number of the specified lens with reference to d-line. By satisfying the conditional expression (2), correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed.

If the corresponding value of the conditional expression (2) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (2) to 50.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (2) may be set to 51.00, 51.50 or 52.00, or further to 52.40.

By setting the upper limit value of the conditional expression (2) to 64.00, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (2) may be set to 63.00, 62.50, 62.00, 61.50, 61.00 or 60.00, or further to 59.50.

The conditional expression (3) appropriately defines the anomalous dispersion characteristics of the specified lens. By satisfying the conditional expression (3), for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum can be favorably corrected.

If the corresponding value of the conditional expression (3) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (3) to 0.547, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (3) may be set to 0.548 or 0.549, or further to 0.550.

The conditional expression (4) appropriately defines the anomalous dispersion characteristics of the specified lens. By satisfying the conditional expression (4), for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum can be favorably corrected.

If the corresponding value of the conditional expression (4) falls outside of the range, the correction of the chromatic aberrations becomes difficult. By setting the lower limit value of the conditional expression (4) to −0.005, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (4) may be set to −0.001.

Note that the upper limit value of the conditional expression (4) may be set to less than 0.040. Accordingly, correction of the reference aberrations, such as the spherical aberration and the coma aberration, and correction of the primary chromatic aberration (achromatization) can be favorably performed. In this case, by setting the upper limit value of the conditional expression (4) to 0.030, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (4) may be set to 0.025, or further to 0.020.

Preferably, the optical system LS according to this embodiment consists of: the aperture stop S; a front group GF disposed closer to an object than the aperture stop S; and a rear group GR disposed closer to an image than the aperture stop S, wherein the front group GF may include the specified lens, and satisfy the following conditional expression (5):

−10.00<|fLZ|/fF<10.00  (5)

where fLZ: a focal length of the specified lens, and

fF: a focal length of the front group GF; in a case where the optical system LS is a zoom optical system, the focal length of the front group GF in the wide angle end state.

The conditional expression (5) defines an appropriate relationship between the focal length of the specified lens and the focal length of the front group GF. By satisfying the conditional expression (5), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (5) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (5) to −9.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (5) may be set to −9.00, −8.50, −8.00, −7.00, −5.00, −3.00, −1.50, −0.05 or 0.05, or further to 0.10.

By setting the upper limit value of the conditional expression (5) to 8.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (5) may be set to 7.50, 6.50, 5.00 or 4.00, or further to 3.00.

The optical system LS according to this embodiment may consist of: the aperture stop S; a front group GF disposed closer to an object than the aperture stop S; and a rear group GR disposed closer to an image than the aperture stop S, wherein the rear group GR may include the specified lens, and satisfy the following conditional expression (6):

−10.00<|fLZ|/fR<10.00  (6)

where fLZ: a focal length of the specified lens, and

fR: a focal length of the rear group GR; in a case where the optical system LS is a zoom optical system, the focal length of the rear group GR in the wide angle end state.

The conditional expression (6) defines an appropriate relationship between the focal length of the specified lens and the focal length of the rear group GR. By satisfying the conditional expression (6), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (6) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (6) to −9.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (6) may be set to −9.00, −8.50, −8.00, −7.00, −5.00, −3.00, −1.50, −0.05 or 0.05, or further to 0.10.

By setting the upper limit value of the conditional expression (6) to 8.50, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (6) may be set to 7.50, 6.50, 5.00 or 4.00, or further to 3.00.

In the optical system LS according to this embodiment, it is desirable that the specified lens satisfy the following conditional expression (7):

0.10<|fLZ|/f<15.00  (7)

where fLZ: a focal length of the specified lens, and

f: a focal length of the optical system; in a case where the optical system LS is a zoom optical system, the focal length of the optical system in the wide angle end state.

The conditional expression (7) defines an appropriate relationship between the focal length of the specified lens and the focal length of the optical system LS. By satisfying the conditional expression (7), the reference aberrations, such as the spherical aberration and the coma aberration, can be favorably corrected.

If the corresponding value of the conditional expression (7) falls outside of the range, the correction of the reference aberrations, such as the spherical aberration and the coma aberration, becomes difficult. By setting the lower limit value of the conditional expression (7) to 0.20, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (7) may be set to 0.30, 0.40 or 0.45, or further to 0.50.

By setting the upper limit value of the conditional expression (7) to 14.20, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (7) may be set to 12.00, 10.00 or 8.50, or further to 7.50.

In the optical system LS according to this embodiment, the specified lens may satisfy the following conditional expression (3-1),

0.555<θgFLZ  (3-1)

The conditional expression (3-1) is an expression similar to the conditional expression (3), and can exert advantageous effects similar to those of the conditional expression (3). By setting the lower limit value of the conditional expression (3-1) to 0.556, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, it is preferable to set the lower limit value of the conditional expression (3-1) to 0.557.

In the optical system LS according to this embodiment, the specified lens may satisfy the following conditional expression (4-1),

0.010<θgFLZ−(0.6418−0.00168×νdLZ)  (4-1)

The conditional expression (4-1) is an expression similar to the conditional expression (4), and can exert advantageous effects similar to those of the conditional expression (4). By setting the lower limit value of the conditional expression (4-1) to 0.011, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, it is preferable to set the lower limit value of the conditional expression (4-1) to 0.012.

Note that the upper limit value of the conditional expression (4-1) may be set to less than 0.030. Accordingly, advantageous effects similar to those of the conditional expression (4) can be achieved. In this case, by setting the upper limit value of the conditional expression (4-1) to 0.028, the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the upper limit value of the conditional expression (4-1) may be set to 0.025 or 0.023, or further to 0.020.

In the optical system LS according to this embodiment, it is desirable that the specified lens satisfy the following conditional expression (8):

DLZ>0.400 [mm]  (8)

where DLZ: a thickness of the specified lens on an optical axis.

The conditional expression (8) appropriately defines the thickness of the specified lens on the optical axis. By satisfying the conditional expression (8), the various aberrations, such as the coma aberration, and the chromatic aberrations (the longitudinal chromatic aberration and the chromatic aberration of magnification), can be favorably corrected.

If the corresponding value of the conditional expression (8) falls outside of the range, the correction of the various aberrations, such as the coma aberration and the chromatic aberrations (the longitudinal chromatic aberration and the chromatic aberration of magnification), becomes difficult. By setting the lower limit value of the conditional expression (8) to 0.450 [mm], the advantageous effects of this embodiment can be further secured. To further secure the advantageous effects of this embodiment, the lower limit value of the conditional expression (8) may be set to 0.490 [mm], 0.550 [mm], 0.580 [mm], 0.650 [mm], 0.680 [mm], 0.750 [mm], 0.800 [mm], 0.850 [mm], 0.880 [mm], 0.950 [mm], 0.980 [mm], 1.050 [mm], 1.100 [mm], 1.140 [mm], 1.250 [mm], or further to 1.350 [mm].

In the optical system LS according to this embodiment, preferably, the specified lens is a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other. Use of glass as the material of the lens has smaller variation in optical characteristics due to temperature than that of resin. In this embodiment, glass can be used as a material of the specified lens. Accordingly, even in the case where the specified lens has a lens surface in contact with air (i.e., a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other), it is preferable because variation in optical characteristics due to temperature is small.

In the optical system LS according to this embodiment, it is desirable that at least one lens surface of an object-side lens surface and an image-side lens surface of the specified lens be in contact with air. Use of glass as the material of the lens has smaller variation in optical characteristics due to temperature than that of resin. In this embodiment, glass can be used as a material of the specified lens. Accordingly, even in a case where a lens surface of the specified lens is in contact with air, it is preferable because the variation in optical characteristics due to temperature is small.

In the optical system LS according to this embodiment, it is desirable that the specified lens be a glass lens. The secular change of the specified lens that is a glass lens is smaller than that of a resin lens. Accordingly, it is preferable because the variation in optical characteristics due to temperature is small.

Subsequently, referring to FIG. 22, a method for manufacturing the optical system LS described above is schematically described. First, at least one lens is arranged (step ST1). At this time, each lens is arranged in a lens barrel so that at least one (specified lens) of the lenses satisfies the conditional expressions (1) to (4) and the like (step ST2). According to such a manufacturing method, the optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected can be manufactured.

EXAMPLES

Optical systems LS according to Examples of this embodiment are described with reference to the drawings. FIGS. 1, 3, 5, 7, 9, 11, 13, 15, 17 and 19 are sectional views showing the configurations and refractive power allocations of optical systems LS {LS(1) to LS(10)} according to First to Tenth Examples. In the sectional views of the optical systems LS(1) to LS(10) according to First to Tenth Examples, the moving direction upon focusing by each focusing lens group from the infinity to a short-distance object is indicated by an arrow accompanied by characters “FOCUSING”. In the sectional views of the optical systems LS(2) to LS(9) according to Second to Ninth Examples, the moving direction of each lens group along the optical axis upon zooming from the wide angle end state (W) to the telephoto end state (T) is indicated by an arrow.

In FIGS. 1, 3, 5, 7, 9, 11, 13, 15, 17 and 19, each lens group is represented by a combination of a symbol G and a numeral, and each lens is represented by a combination of a symbol L and a numeral. In this case, to prevent complication due to increase in the types and numbers of symbols and numerals, the lens groups and the like are represented using the combinations of symbols and numerals independently on an Example-by-Example basis. Accordingly, even when the same combination of a symbol and a numeral is used among Examples, such usage does not mean the same configuration.

Tables 1 to 10 are shown below. Among the drawings, Table 1 is a table showing each data item in First Example, Table 2 is that in Second Example, Table 3 is that in Third Example, Table 4 is that in Fourth Example, Table 5 is that in Fifth Example, Table 6 is that in Sixth Example, Table 7 is that in Seventh Example, Table 8 is that in Eighth Example, Table 9 is that in Ninth Example, and Table 10 is that in Tenth Example. In each Example, as targets of calculation of aberration characteristics, d-line (wavelength λ=587.6 nm), g-line (wavelength λ=435.8 nm), C-line (wavelength λ=656.3 nm), and F-line (wavelength λ=486.1 nm) are selected.

In the table of [General Data], f indicates the focal length of the entire lens system, FNO indicates the f-number, 2ω indicates the angle of view (the unit is ° (degrees), and ω is the half angle of view), and Y indicates the image height. TL indicates a distance obtained by adding BF to the distance from the lens foremost surface to the lens last surface on the optical axis upon focusing on infinity. BF indicates the distance (back focus) from the lens last surface to the image surface I on the optical axis upon focusing on infinity. fF indicates the focal length of the front group, and fR indicates the focal length of the rear group. Note that in a case where the optical system is a zoom optical system, these values are indicated for each of zoom states at the wide-angle end (W), the intermediate focal length (M) and the telephoto end (T).

In the table of [Lens Data], Surface Number indicates the order of the optical surface from the object side along the direction in which the ray travels, R indicates the radius of curvature (the surface whose center of curvature resides on the image side is regarded to have a positive value) of each optical surface, D indicates the surface distance which is the distance to the next lens surface (or the image surface) from each optical surface on the optical axis, nd is the refractive index of the material of the optical member for d-line, νd indicates the Abbe number of the material of the optical member with respect to d-line, and θgF indicates the partial dispersion ratio of the material of the optical member. The radius of curvature “∞” indicates a plane or an opening. (Aperture Stop S) indicates an aperture stop S. The description of the air refractive index nd=1.00000 is omitted. In a case where the optical surface is an aspherical surface, the surface number is assigned * symbol, and the field of the radius of curvature R indicates the paraxial radius of curvature.

The refractive index of the optical member for g-line (wavelength λ=435.8 nm) is indicated by ng. The refractive index of the optical member for F-line (wavelength λ=486.1 nm) is indicated by nF. The refractive index of the optical member for C-line (wavelength λ=656.3 nm) is indicated by nC. Here, the partial dispersion ratio θgF of the material of the optical member is defined by the following expression (A).

θgF=(ng−nF)/(nF−nC)  (A)

In the table of [Aspherical Surface Data], the shape of the aspherical surface indicated in [Lens Data] is indicated by the following expression (B). X(y) indicates the distance (sag amount) from the tangent plane at the vertex of the aspherical surface to the position on the aspherical surface at the height y along the optical axis direction. R indicates the radius of curvature (paraxial radius of curvature) of the reference spherical surface. κ indicates the conic constant. Ai indicates the i-th aspherical coefficient. “E-n” indicates “×10^(−n)”. For example, 1.234E-05=1.234×10⁻⁵. Note that the second-order aspherical coefficient A2 is zero, and the description thereof is omitted.

X(y)=(y ² /R)/{1+(1−κ×y ² /R ²)^(1/2) }+A4×y ⁴ +A6×y ⁶ +A8×y ⁸ +A10×y ¹⁰ +A12×y ¹²  (B)

In a case where the optical system is not a zoom optical system, f indicates the focal length of the entire lens system, and β indicates the photographing magnification, as [Variable Distance Data on Short-Distance Photographing]. The table of [Variable Distance Data on Short-Distance Photographing] indicates the surface distance at the surface number where the surface distance is “Variable” in [Lens Data] corresponding to each focal length and photographing magnification.

In the case where the optical system is the zoom optical system, the surface distance at the surface number where the surface distance is “Variable” in [Lens Data] corresponding to each of zooming states at the wide angle end (W), the intermediate focal length (M) and the telephoto end (T) are indicated as [Variable Distance Data on Zoom Photographing].

The table of [Lens Group Data] shows the first surface (the surface closest to the object) and the focal length of each lens group.

The table of [Conditional Expression Corresponding Value] shows the value corresponding to each conditional expression.

Hereinafter, at all the data values, the listed focal length f, the radius of curvature R, the surface distance D, other lengths and the like are represented with “mm” if not otherwise specified. However, even after subjected to proportional scaling in or out, the optical system can achieve equivalent optical performance. Accordingly, the representation is not limited thereto.

The descriptions of the tables so far are common to all the Examples. Redundant descriptions are hereinafter omitted.

First Example

First Example is described with reference to FIGS. 1 and 2A, 2B and 2C, and Table 1. FIG. 1 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to First Example of this embodiment. The optical system LS(1) according to First Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; and a third lens group G3 having a positive refractive power. Upon focusing from the infinity object to the short-distant (finite distant) object, the second lens group G2 moves toward the object along the optical axis. The aperture stop S is disposed in the third lens group G3. A sign (+) or (−) assigned to each lens group symbol indicates the refractive power of each lens group. This indication similarly applies to all the following Examples.

The first lens group G1 consists of, in order from the object: a positive meniscus lens L11 having a convex surface facing the object; a biconvex positive lens L12; and a cemented lens consisting of a biconvex positive lens L13 and a biconcave negative lens L14.

The second lens group G2 consists of, in order from the object, a cemented lens consisting of a positive meniscus lens L21 having a concave surface facing the object, and a biconcave negative lens L22.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a biconvex positive lens L32 and a biconcave negative lens L33; a biconvex positive lens L34; a cemented lens consisting of a biconcave negative lens L35 and a biconvex positive lens L36; and a cemented lens consisting of a biconcave negative lens L37 and a biconvex positive lens L38. An aperture stop S is disposed between the negative lens L33 (of the cemented lens) and the positive lens L34 of the third lens group G3. An image surface I is disposed on the image side of the third lens group G3. In this Example, the positive lens L32 of the third lens group G3 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like.

In this Example, the positive meniscus lens L11, the positive lens L12, the cemented lens consisting of the positive lens L13 and the negative lens L14, the cemented lens consisting of the positive meniscus lens L21 and the negative lens L22, the positive lens L31, and the cemented lens consisting of the positive lens L32 and the negative lens L33 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L34, the cemented lens consisting of the negative lens L35 and the positive lens L36, and the cemented lens consisting of the negative lens L37 and the positive lens 38 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 1 lists values of data on the optical system according to First Example.

TABLE 1 [General Data] f 101.836 FNO 1.450 2ω 23.858 Y 21.630 TL 150.819 BF 40.419 fF 183.828 fR 67.854 [Lens Data] Surface Number R D nd νd θgF 1 196.23220 5.196 1.59349 67.00 0.5366 2 2286.18150 0.100 3 106.11310 8.799 1.49782 82.57 0.5386 4 −590.58120 0.100 5 69.87930 12.053  1.49782 82.57 0.5386 6 −214.24630 3.500 1.72047 34.71 0.5834 7 180.96130  D7(Variable) 8 −154.49370 4.000 1.65940 26.87 0.6327 9 −81.01520 2.500 1.48749 70.32 0.5291 10 47.84150 D10(Variable) 11 60.72420 7.163 2.00100 29.13 0.5995 12 −460.33830 0.100 13 208.41160 7.434 1.65240 55.27 0.5607 14 −53.40870 1.800 1.69895 30.13 0.6021 15 29.04580 5.561 16 ∞ 1.600 (Aperture Stop S) 17 147.67940 6.054 1.59319 67.90 0.5440 18 −46.44860 0.100 19 −46.85960 1.600 1.72047 34.71 0.5834 20 25.22680 8.064 1.77250 49.62 0.5518 21 −295.74160 2.754 22 −48.05560 1.800 1.58144 40.98 0.5763 23 109.52130 5.418 2.00100 29.13 0.5995 24 −58.12710 BF [Variable Distance Data on Short-Distance Photographing] Upon Upon focusing on Upon focusing on focusing an intermediate a short-distance on infinity distance object object f = 101.836 β = −0.033 β = −0.134 D7 7.730 10.644 19.730 D10 16.973 14.059 4.973 [Lens Group Data] Group First surface Focal length G1 1 91.612 G2 8 −80.287 G3 11 78.292 [Conditional Expression Corresponding Value] <Positive lens L32(fLZ = 65.904)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.013 Conditional Expression(2)νdLZ = 55.27 Conditional Expression(3), (3-1)θgFLZ = 0.5607 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0118 Conditional Expression(5)|fLZ|/fF = 0.359 Conditional Expression(7)|fLZ|/f = 0.647 Conditional Expression(8)DLZ = 7.434

FIG. 2A shows various aberration graphs of the optical system according to First Example upon focusing on infinity. FIG. 2B shows various aberration graphs of the optical system according to First Example upon focusing on an intermediate distant object. FIG. 2C shows various aberration graphs of the optical system according to First Example upon focusing on a short-distant (very short distance) object. In each graph upon focusing on infinity, FNO indicates the f-number, and Y indicates the image height. In each aberration graph upon focusing on the intermediate distant object or focusing on the short distant object, NA indicates the numerical aperture, and Y indicates the image height. The spherical aberration graph indicates the value of the f-number or the numerical aperture that corresponds to the maximum diameter. The astigmatism graph and the distortion graph each indicate the maximum value of the image height. The coma aberration graph indicates the value of the corresponding image height. d indicates d-line (wavelength λ=587.6 nm), g indicates g-line (wavelength λ=435.8 nm), C indicates C-line (wavelength λ=656.3 nm), and F indicates F-line (wavelength λ=486.1 nm). In the astigmatism graph, a solid line indicates a sagittal image surface, and a broken line indicates a meridional image surface. Note that also in the following aberration graphs in each Example, symbols similar to those in this Example are used. Redundant description is omitted.

The various aberration graphs show that the optical system according to First Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Second Example

Second Example is described with reference to FIGS. 3 and 4A, 4B and 4C, and Table 2. FIG. 3 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Second Example of this embodiment. The optical system LS(2) according to Second Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 3. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object. In this Example, the positive meniscus lens L13 of the first lens group G1 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; and a cemented lens consisting of a biconvex positive lens L23, and a biconcave negative lens L24. Upon focusing from the infinity object to the short-distant (finite distant) object, the second lens group G2 moves toward the object along the optical axis. The negative meniscus lens L21 is a hybrid type lens that includes a lens main body made of glass, and a resin layer provided on the object-side surface of the lens main body. The object-side surface of the resin layer is an aspherical surface. The negative meniscus lens L21 is a composite type aspherical surface lens. In [Lens Data] described later, the surface number 6 indicates the object-side surface of the resin layer, the surface number 7 indicates the image-side surface of the resin layer and the object-side surface of the lens main body (a surface on which both the elements are in contact), and the surface number 8 indicates the image-side surface of the lens main body.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; and a cemented lens consisting of a biconvex positive lens L32 and a biconcave negative lens L33. The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming.

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a biconcave negative lens L41 and a positive meniscus lens L42 having a convex surface facing the object; a positive meniscus lens L43 having a concave surface facing the object; and a biconcave negative lens L44. The fourth lens group G4 constitutes a vibration-proof lens group that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I). Note that a fixed aperture stop (flare cut stop) Sa is disposed adjacent to the image side of the negative lens L44.

The fifth lens group G5 consists of, in order from the object: a biconvex positive lens L51; and a cemented lens consisting of a biconvex positive lens L52 and a negative meniscus lens L53 having a concave surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the cemented lens consisting of the positive lens L23 and the negative lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the positive lens L32 and the negative lens L33, the cemented lens consisting of the negative lens L41 and the positive meniscus lens L42, the positive meniscus lens L43, the negative lens L44, the positive lens L51, and the cemented lens consisting of the positive lens L52 and the negative meniscus lens L53 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 2 lists values of data on the optical system according to Second Example.

TABLE 2 [General Data] Zooming ratio = 7.350 W M T f 18.562 35.210 136.429 FNO 3.565 4.261 5.725 2ω 79.728 43.847 11.914 Y 14.750 14.750 14.750 TL 147.043 159.329 197.172 BF 38.330 47.731 64.149 fF −21.071 −26.512 −62.674 fR 34.551 33.436 30.388 [Lens Data] Surface Number R D nd νd θgF  1 160.06970 2.000 1.80518 25.45 0.6157  2 72.85900 6.800 1.60311 60.69 0.5411  3 −2257.79640 0.100  4 65.68570 4.950 1.66106 56.09 0.5512  5 237.70390  D5(Variable)  6* 170.00150 0.150 1.55389 38.23 0.5985  7 152.15480 1.200 1.80610 40.97 0.5688  8 14.79840 6.030  9 −50.40310 1.000 1.80610 40.97 0.5688 10 41.82650 0.430 11 28.25640 5.330 1.84666 23.78 0.6191 12 −39.95900 1.000 1.77250 49.62 0.5518 13 103.33450 D13(Variable) 14 ∞ 0.400 (Aperture Stop S) 15 66.90190 2.930 1.48749 70.31 0.5291 16 −27.85660 0.100 17 23.35290 3.850 1.59319 67.90 0.5440 18 −23.34450 1.000 1.75520 27.57 0.6093 19 172.44420 D19(Variable) 20 −28.46170 1.180 1.77250 49.62 0.5518 21 18.92800 3.000 1.85026 32.35 0.5947 22 225.68110 0.500 23 −62.96650 2.400 1.75520 27.57 0.6093 24 −23.41100 0.430 25 −55.81190 1.000 1.80610 40.97 0.5688 26 107.88980 0.800 27 ∞ D27(Variable) 28 259.73390 4.030 1.54814 45.79 0.5686 29 −24.93830 0.400 30 69.14960 6.430 1.48749 70.31 0.5291 31 −17.33550 1.300 1.90366 31.27 0.5948 32 −57.92460 BF [Aspherical Surface Data] 6th Surface κ = 1.000, A4 = 5.49E−06, A6 = −3.19E−08 A8 = 1.01E−10, A10 = −1.80E−13, A12 = 0.00E+00 [Variable Distance Data on Zoom Photographing] W M T D5 2.566 18.230 53.226 D13 29.462 16.684 3.112 D19 2.267 5.702 11.422 D27 9.761 6.327 0.607 [Lens Group Data] Group First surface Focal length G1 1 101.950 G2 6 −15.773 G3 14 25.098 G4 20 −35.397 G5 28 42.292 [Conditional Expression Corresponding Value] <Positive meniscus lens L13(fLZ = 135.752)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.027 Conditional Expression(2)νdLZ = 56.09 Conditional Expression(3), (3-1)θgFLZ = 0.5512 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0036 Conditional Expression(5)|fLZ|/fF = −6.443 Conditional Expression(7)|fLZ|/f = 7.314 Conditional Expression(8)DLZ = 4.950

FIG. 4A shows various aberration graphs of the optical system according to Second Example upon focusing on infinity in the wide angle end state. FIG. 4B shows various aberration graphs of the optical system according to Second Example upon focusing on infinity in the intermediate focal length state. FIG. 4C shows various aberration graphs of the optical system according to Second Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Second Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Third Example

Third Example is described with reference to FIGS. 5 and 6A, 6B and 6C, and Table 3. FIG. 5 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Third Example of this embodiment. The optical system LS(3) according to Third Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fourth lens groups G1 to G4 move in directions indicated by arrows in FIG. 5. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object. In this Example, the positive meniscus lens L13 of the first lens group G1 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a negative meniscus lens L22 having a concave surface facing the object; a biconvex positive lens L23; and a biconcave negative lens L24.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a positive meniscus lens L32 having a convex surface facing the object, and a negative meniscus lens L33 having a convex surface facing the object; and a biconvex positive lens L34. The third lens group G3 constitutes a vibration-proof lens group that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I). The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The positive lens L31 has opposite lens surfaces that are aspherical surfaces.

The fourth lens group G4 consists of a negative meniscus lens L41 having a convex surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the image along the optical axis.

The fifth lens group G5 consists of a biconvex positive lens L51. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface. An optical filter FL is disposed between the fifth lens group G5 and the image surface I. The optical filter FL may be, for example, an NC filter (neutral color filter), a color filter, a polarizing filter, an ND filter (neutral density filter), an IR filter (infrared cutoff filter) or the like.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative meniscus lens L22, the positive lens L23, and the negative lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the positive meniscus lens L32 and the negative meniscus lens L33, the positive lens L34, the negative meniscus lens L41, and the positive lens L51 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 3 lists values of data on the optical system according to Third Example.

TABLE 3 [General Data] Zooming ratio = 32.853 W M T f 4.432 10.612 145.612 FNO 3.517 4.350 7.648 2ω 85.088 40.382 3.059 Y 3.300 4.000 4.000 TL 68.023 68.791 99.945 BF 0.400 0.400 0.400 fF −7.489 −9.624 −57.480 fR 19.941 22.639 −39.152 [Lens Data] Surface Number R D nd νd θgF  1 85.30695 0.950 1.85026 32.35 0.5947  2 35.10887 3.750 1.49700 81.73 0.5371  3 −199.02101 0.100  4 35.51343 2.650 1.62731 59.30 0.5583  5 407.61568  D5(Variable)  6 119.76222 0.500 1.78800 47.35 0.5559  7 6.54053 3.500  8 −12.14658 0.550 1.90366 31.31 0.5947  9 −539.42059 0.100 10 17.08985 2.600 1.92286 20.88 0.6390 11 −15.28142 0.315 12 −11.12109 0.550 1.80440 39.61 0.5719 13 165.37200 D13(Variable) 14 ∞ 0.700 (Aperture Stop S)  15* 7.30358 2.200 1.49710 81.56 0.5385  16* −22.98363 0.100 17 7.85006 2.200 1.53172 48.78 0.5622 18 274.32025 0.400 1.91082 35.25 0.5822 19 5.97566 0.650 20 14.69669 1.700 1.49700 81.73 0.5371 21 −20.28040 D21(Variable) 22 20.19905 0.600 1.49700 81.73 0.5371 23 6.78416 D23(Variable)  24* 10.00000 2.200 1.53113 55.75 0.5628 25 −164.68126 0.600 26 ∞ 0.210 1.51680 63.88 0.5360 27 ∞ 0.450 28 ∞ 0.500 1.51680 63.88 0.5360 29 ∞ BF [Aspherical Surface Data] 15th Surface κ = 0.896, A4 = 1.84310E−04, A6 = −1.16172E−06 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 16th Surface κ = 1.000, A4 = 1.84659E−04, A6 = −7.65864E−07 A8 = 4.06410E−08, A10 = 0.00000E+00, A12 = 0.00000E+00 24th Surface κ = 2.716 , A4 = −3.76188E−05, A6 = −3.07675E−07 A8 = 0.00000E+00, A10 = 0.00000E+00, A12 = 0.00000E+00 [Variable Distance Data on Zoom Photographing] W M T D5 0.742 10.482 38.914 D13 26.839 13.689 2.261 D21 3.294 9.196 14.996 D23 8.674 6.949 15.300 [Lens Group Data] Group First surface Focal length G1 1 53.961 G2 6 −6.091 G3 14 11.902 G4 22 −20.863 G5 24 17.828 [Conditional Expression Corresponding Value] <Positive meniscus lens L13(fLZ = 61.845)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.016 Conditional Expression(2)νdLZ = 59.30 Conditional Expression(3), (3-1)θgFLZ = 0.5583 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0161 Conditional Expression(5)|fLZ|/fF = −8.258 Conditional Expression(7)|fLZ|/f = 13.954 Conditional Expression(8)DLZ = 2.650

FIG. 6A shows various aberration graphs of the optical system according to Third Example upon focusing on infinity in the wide angle end state. FIG. 6B shows various aberration graphs of the optical system according to Third Example upon focusing on infinity in the intermediate focal length state. FIG. 6C shows various aberration graphs of the optical system according to Third Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Third Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Fourth Example

Fourth Example is described with reference to FIGS. 7 and 8A, 8B and 8C, and Table 4. FIG. 7 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Fourth Example of this embodiment. The optical system LS(4) according to Fourth Example consists of, in order from the object: a first lens group G1 having a negative refractive power; a second lens group G2 having a positive refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 7. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a negative meniscus lens L11 having a convex surface facing the object; a negative meniscus lens L12 having a convex surface facing the object; a biconcave negative lens L13; and a biconvex positive lens L14. In this Example, the negative meniscus lens L11, the negative meniscus lens L12 and the negative lens L13 of the first lens group G1 correspond to a specified lens that satisfies the conditional expressions (1) to (4) and the like. The negative meniscus lens L11 has an image-side lens surface that is an aspherical surface. The negative meniscus lens L12 has an image-side lens surface that is an aspherical surface.

The second lens group G2 consists of, in order from the object: a positive meniscus lens L21 having a convex surface facing the object; and a cemented lens consisting of a negative meniscus lens L22 having a convex surface facing the object, and a positive meniscus lens L23 having a convex surface facing the object. The aperture stop S is disposed adjacent to the image side of the positive meniscus lens L23, and moves with the second lens group G2 upon zooming.

The third lens group G3 consists of, in order from the object: a cemented lens consisting of a biconcave negative lens L31 and a biconvex positive lens L32; and a biconvex positive lens L33. The positive lens L32 has an image-side lens surface that is an aspherical surface.

The fourth lens group G4 consists of a biconcave negative lens L41. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the image along the optical axis.

The fifth lens group G5 consists of a positive meniscus lens L51 having a concave surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5. The positive meniscus lens L51 has an image-side lens surface that is an aspherical surface.

In this Example, the negative meniscus lens L11, the negative meniscus lens L12, the negative lens L13, the positive lens L14, the positive meniscus lens L21, and the cemented lens consisting of the negative meniscus lens L22 and the positive meniscus lens L23 constitute the front group GF disposed closer to the object than the aperture stop S. The cemented lens consisting of the negative lens L31 and the positive lens L32, the positive lens L33, the negative lens L41, and the positive meniscus lens L51 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 4 lists values of data on the optical system according to Fourth Example.

TABLE 4 [General Data] Zooming ratio = 2.018 W M T f 14.420 20.000 29.100 FNO 4.073 4.072 4.066 2ω 115.788 91.602 67.988 Y 20.500 20.500 20.500 TL 121.803 110.314 103.827 BF 15.000 23.093 30.403 fF 12.336 18.020 29.688 fR −249.182 −357.800 −1948.200 [Lens Data] Surface Number R D nd νd θgF  1 92.62990 3.000 1.68348 54.80 0.5501  2* 15.67070 4.579  3 28.37140 2.900 1.68348 54.80 0.5501  4* 21.12170 12.704   5 −37.55490 1.900 1.68348 54.80 0.5501  6 88.75380 0.100  7 98.47090 5.412 1.86109 34.82 0.5864  8 −53.58090  D8(Variable)  9 20.49420 4.232 1.59349 67.00 0.5358 10 164.24190 3.859 11 16.69960 1.200 1.88300 40.66 0.5668 12 8.68950 4.536 1.52748 56.00 0.5481 13 180.51560 2.500 14 ∞ D14(Variable) (Aperture Stop S) 15 −357.35260 1.100 1.81600 46.59 0.5567 16 14.59730 3.507 1.49782 82.57 0.5386  17* −561.45740 1.192 18 36.97580 6.029 1.49782 82.57 0.5386 19 −12.85510 D19(Variable) 20 −20.05630 1.000 1.55199 62.60 0.5377 21 48.74520 D21(Variable) 22 −64.12910 1.200 1.51680 63.88 0.5360  23* −53.18510 BF [Aspherical Surface Data] 2nd Surface κ = 0.000, A4 = −9.16E−07, A6 = 3.00E−08 A8 = −1.16E−10, A10 = 1.53E−13, A12 = 0.00E+00 4th Surface κ = 0.000, A4 = 3.15E−05, A6 = −2.15E−08 A8 = 4.46E−10, A10 = −1.10E−12, A12 = 2.22E−15 17th Surface κ = 1.000, A4 = 5.91E−05, A6 = 1.04E−07 A8 = 3.02E−09, A10 = −4.09E−11, A12 = 0.00E+00 23rd Surface κ = 1.000, A4 = 3.06E−05, A6 = 2.73E−08 A8 = −4.72E−11, A10 = 7.08E−13, A12 = 0.00E+00 [Variable Distance Data on Zoom Photographing] W M T D8 33.229 16.105 1.500 D14 2.125 2.115 2.279 D19 2.000 2.982 4.774 D21 8.500 5.069 3.922 [Lens Group Data] Group First surface Focal length G1 1 −23.700 G2 9 28.300 G3 15 28.700 G4 20 −25.600 G5 22 581.300 [Conditional Expression Corresponding Value] <Negative meniscus lens L11(fLZ = −28.041)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)θgFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(5)|fLZ|/fF = 2.273 Conditional Expression(7)|fLZ|/f = 1.945 Conditional Expression(8)DLZ = 3.000 <Negative meniscus lens L12(fLZ = −144.389)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)θgFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(5)|fLZ|/fF = 11.705 Conditional Expression(7)|fLZ|/f = 10.013 Conditional Expression(8)DLZ = 2.900 <Negative lens L13(fLZ = −38.375)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)θgFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(5)|fLZ|/fF = 3.111 Conditional Expression(7)|fLZ|/f = 2.661 Conditional Expression(8)DLZ = 1.900

FIG. 8A shows various aberration graphs of the optical system according to Fourth Example upon focusing on infinity in the wide angle end state. FIG. 8B shows various aberration graphs of the optical system according to Fourth Example upon focusing on infinity in the intermediate focal length state. FIG. 8C shows various aberration graphs of the optical system according to Fourth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Fourth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Fifth Example

Fifth Example is described with reference to FIGS. 9 and 10A, 10B and 10C and Table 5. FIG. 9 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Fifth Example of this embodiment. The optical system LS(5) according to Fifth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; and a fifth lens group G5 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the second lens groups G2 and the fourth lens group G4 move in directions indicated by arrows in FIG. 9. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; a positive meniscus lens L23 having a convex surface facing the object; and a biconcave negative lens L24. In this Example, the negative meniscus lens L21, the negative lens L22 and the negative lens L24 of the second lens group G2 correspond to a specified lens that satisfies the conditional expressions (1) to (4) and the like.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a plano-convex positive lens L32 having a convex surface facing the object; a positive meniscus lens L33 having a convex surface facing the object; a biconcave negative lens L34; and a cemented lens consisting of a biconvex positive lens L35, and a biconcave negative lens L36. The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming.

The fourth lens group G4 consists of, in order from the object: a biconvex positive lens L41; and a cemented lens consisting of a negative meniscus lens L42 having a convex surface facing the object, and a positive meniscus lens L43 having a convex surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the object along the optical axis.

The fifth lens group G5 consists of, in order from the object: a negative meniscus lens L51 having a convex surface facing the object; a cemented lens consisting of a biconvex positive lens L52, and a biconcave negative lens L53; a plano-concave negative lens L54 having a concave surface facing the image; a biconvex positive lens L55; and a positive meniscus lens L56 having a convex surface facing the object. An image surface I is disposed on the image side of the fifth lens group G5. The cemented lens consisting of the positive lens L52 and the negative lens L53, and the negative lens L54 of the fifth lens group G5 constitute a vibration-proof lens group (partial group) that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I).

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive meniscus lens L23, and the negative lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the positive lens L32, the positive meniscus lens L33, the negative lens L34, the cemented lens consisting of the positive lens L35 and the negative lens L36, the positive lens L41, the cemented lens consisting of the negative meniscus lens L42 and the positive meniscus lens L43, the negative meniscus lens L51, the cemented lens consisting of the positive lens L52 and the negative lens L53, the negative lens L54, the positive lens L55, and the positive meniscus lens L56 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 5 lists values of data on the optical system according to Fifth Example.

TABLE 5 [General Data] Zooming ratio = 2.745 W M T f 71.400 140.000 196.000 FNO 2.865 2.937 2.862 2ω 33.666 17.094 12.198 Y 21.600 21.600 21.600 TL 245.880 245.880 245.880 BF 53.818 53.818 53.818 fF −86.769 −153.380 −238.187 fR 67.044 63.889 67.044 [Lens Data] Surface Number R D nd νd θgF 1 120.99680 2.800 1.95000 29.37 0.6002 2 87.12840 9.900 1.49782 82.57 0.5386 3 −1437.70340 0.100 4 97.36390 7.700 1.45600 91.37 0.5342 5 657.25840  D5(Variable) 6 73.32110 2.400 1.68348 54.80 0.5501 7 33.43260 10.250  8 −134.27600 2.000 1.62731 59.30 0.5584 9 104.31770 2.000 10 55.93640 4.400 1.84666 23.78 0.6192 11 193.35670 3.550 12 −72.87930 2.200 1.62731 59.30 0.5584 13 610.02530 D13(Variable) 14 ∞ 2.500 (Aperture Stop S) 15 667.50610 3.700 1.83481 42.73 0.5648 16 −127.34870 0.200 17 91.74030 3.850 1.59319 67.90 0.5440 18 ∞ 0.200 19 52.70200 4.900 1.49782 82.57 0.5386 20 340.98300 2.120 21 −123.54810 2.200 2.00100 29.13 0.5995 22 172.97240 4.550 23 104.97670 5.750 1.90265 35.72 0.5804 24 −70.95230 2.200 1.58144 40.98 0.5763 25 42.96180 D25(Variable) 26 69.69710 4.800 1.49782 82.57 0.5386 27 −171.29750 0.100 28 43.33010 2.000 1.95000 29.37 0.6002 29 28.62160 5.550 1.59319 67.90 0.5440 30 175.11530 D30(Variable) 31 59.19620 1.800 1.80400 46.60 0.5575 32 33.42540 5.150 33 127.38170 3.350 1.84666 23.78 0.6192 34 −127.38220 1.600 1.68348 54.80 0.5501 35 43.09820 2.539 36 ∞ 1.600 1.95375 32.32 0.5901 37 71.19380 3.750 38 107.03200 3.850 1.59319 67.90 0.5440 39 −166.05150 0.150 40 49.83700 3.900 1.71999 50.27 0.5527 41 161.11230 BF [Variable Distance Data on Zoom Photographing] W M T D5 2.882 35.671 50.879 D13 50.300 17.511 2.303 D25 17.270 14.466 17.270 D30 2.000 4.804 2.000 [Lens Group Data] Group First surface Focal length G1 1 143.763 G2 6 −45.569 G3 14 90.760 G4 26 60.061 G5 31 −112.026 [Conditional Expression Corresponding Value] <Negative meniscus lens L21(fLZ = −92.166)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)θgFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(5)|fLZ|/fF = −1.062 Conditional Expression(7)|fLZ|/f = 1.291 Conditional Expression(8)DLZ = 2.400 <Negative lens L22(fLZ = −93.285)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.016 Conditional Expression(2)νdLZ = 59.30 Conditional Expression(3), (3-1)θgFLZ = 0.5584 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0162 Conditional Expression(5)|fLZ|/fF = −1.075 Conditional Expression(7)|fLZ|/f = 1.307 Conditional Expression(8)DLZ = 2.000 <Negative lens L24(fLZ = −103.650)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.016 Conditional Expression(2)νdLZ = 59.30 Conditional Expression(3), (3-1)θgFLZ = 0.5584 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0162 Conditional Expression(5)|fLZ|/fF = −1.195 Conditional Expression(7)|fLZ|/f = 1.452 Conditional Expression(8)DLZ = 2.200

FIG. 10A shows various aberration graphs of the optical system according to Fifth Example upon focusing on infinity in the wide angle end state. FIG. 10B shows various aberration graphs of the optical system according to Fifth Example upon focusing on infinity in the intermediate focal length state. FIG. 10C shows various aberration graphs of the optical system according to Fifth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Fifth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Sixth Example

Sixth Example is described with reference to FIGS. 11 and 12A, 12B and 12C, and Table 6. FIG. 11 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Sixth Example of this embodiment. The optical system LS(6) according to Sixth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; and a fifth lens group G5 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 11. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object, a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a positive meniscus lens L12 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a biconcave negative lens L21; a biconcave negative lens L22; and a positive meniscus lens L23 having a convex surface facing the object. The negative meniscus lens L21 has an object-side lens surface that is an aspherical surface. The negative lens L21 has an image-side lens surface that is an aspherical surface.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a biconvex positive lens L32 and a biconcave negative lens L33; and a cemented lens consisting of a negative meniscus lens L34 having a convex surface facing the object, and a positive meniscus lens L35 having a convex surface facing the object. The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. In this Example, the positive lens L31 of the third lens group G3 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like. The positive lens L31 has an object-side lens surface that is an aspherical surface.

The fourth lens group G4 consists of, in order from the object: a negative meniscus lens L41 having a concave surface facing the object; and a biconvex positive lens L42. Upon focusing from the infinity object to the short-distant (finite distant) object, the fourth lens group G4 moves toward the object along the optical axis, and the fifth lens group G5 moves toward the image along the optical axis. The positive lens L42 has an image-side lens surface that is an aspherical surface.

The fifth lens group G5 consists of a biconcave negative lens L51. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an image-side lens surface that is an aspherical surface.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive meniscus lens L12, the negative lens L21, the negative lens L22, and the positive meniscus lens L23 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the positive lens L32 and the negative lens L33, the cemented lens consisting of the negative meniscus lens L34 and the positive meniscus lens L35, the negative meniscus lens L41, the positive lens L42, and the negative lens L51 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 6 lists values of data on the optical system according to Sixth Example.

TABLE 6 [General Data] Zooming ratio = 2.747 W M T f 24.720 50.011 67.898 FNO 4.074 4.107 4.075 2ω 84.838 44.346 32.369 Y 20.735 21.600 21.600 TL 122.000 132.823 150.965 BF 24.245 49.372 55.721 fF −35.120 −41.087 −52.774 fR 32.395 33.090 34.250 [Lens Data] Surface Number R D nd νd θgF  1 79.38040 2.150 1.84666 23.80 0.6215  2 51.02390 8.034 1.75500 52.33 0.5475  3 1073.05060 D3(Variable)  4 −787.39720 1.800 1.65550 46.34 0.5651  5* 15.02170 8.908  6 −58.26290 1.350 1.49782 82.57 0.5138  7 54.06630 0.100  8 30.99440 4.650 1.77396 24.31 0.6142  9 194.90020 D9(Variable) 10 ∞ 1.500 (Aperture Stop S)  11* 32.88300 3.765 1.68348 54.80 0.5501 12 −482.16640 0.102 13 20.12780 4.081 1.59319 67.90 0.5440 14 −99.80710 1.500 1.76634 38.61 0.5791 15 25.27260 0.342 16 34.24310 2.000 1.95375 32.33 0.5916 17 14.97810 3.842 1.56992 38.72 0.5789 18 73.96770 D9(Variable) 19 −17.50130 0.900 1.80415 28.31 0.6015 20 −23.09180 0.100 21 77.91830 6.224 1.59201 67.02 0.5358  22* −22.62830 D22(Variable)  23 −344.21280 0.900 1.63563 48.44 0.5614  24* 92.95460 BF [Aspherical Surface Data] 5th Surface κ = 0.000, A4 = 2.68E−05, A6 = 3.48E−08 A8 = 1.69E−10, A10 = 0.00E+00, A12 = 0.00E+00 11th Surface κ = 1.000, A4 = −9.83E−07, A6 = −4.69E−09 A8 = 2.28E−10, A10 = −1.34E−12, A12 = 0.00E+00 22nd Surface κ = 1.000, A4 = 2.57E−05, A6 = −7.85E−09 A8 = 1.82E−10, A10 = −5.72E−13, A12 = 0.00E+00 24th Surface κ = 1.000, A4 = −2.86E−06, A6 = 3.10E−08 A8 = −9.24E−11, A10 = 2.91E−13, A12 = 0.00E+00 [Variable Distance Data on Zoom Photographing] W M T D3 2.143 14.848 31.406 D9 24.905 6.054 3.035 D18 8.153 5.745 6.556 D22 10.307 4.557 2.000 [Lens Group Data] Group First surface Focal length G1 1 121.600 G2 4 −25.300 G3 10 43.600 G4 19 40.800 G5 23 −115.100 [Conditional Expression Corresponding Value] <Positive lens L31(fLZ = 45.174)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)θgFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(6)|fLZ|/fR = 1.394 Conditional Expression(7)|fLZ|/f = 1.827 Conditional Expression(8)DLZ = 3.765

FIG. 12A shows various aberration graphs of the optical system according to Sixth Example upon focusing on infinity in the wide angle end state. FIG. 12B shows various aberration graphs of the optical system according to Sixth Example upon focusing on infinity in the intermediate focal length state. FIG. 12C shows various aberration graphs of the optical system according to Sixth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Sixth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Seventh Example

Seventh Example is described with reference to FIGS. 13 and 14A, 14B and 14C, and Table 7. FIG. 13 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Seventh Example of this embodiment. The optical system LS(7) according to Seventh Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; a fifth lens group G5 having a positive refractive power; a sixth lens group G6 having a positive refractive power; and a seventh lens group G7 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to seventh lens groups G1 to G7 move in directions indicated by arrows in FIG. 13. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a positive meniscus lens L12 having a convex surface facing the object; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; a biconvex positive lens L23; and a negative meniscus lens L24 having a concave surface facing the object. The negative meniscus lens L21 has an object-side lens surface that is an aspherical surface.

The third lens group G3 consists of, in order from the object: a positive meniscus lens L31 having a convex surface facing the object; and a biconvex positive lens L32. The aperture stop S is disposed adjacent to the object side of the positive meniscus lens L31, and moves with the third lens group G3 upon zooming. The positive meniscus lens L31 has an object-side lens surface that is an aspherical surface.

The fourth lens group G4 consists of, in order from the object, a cemented lens consisting of a negative meniscus lens L41 having a convex surface facing the object, and a biconvex positive lens L42.

The fifth lens group G5 consists of, in order from the object: a negative meniscus lens L51 having a concave surface facing the object; and a biconvex positive lens L52. Upon focusing from the infinity object to the short-distant (finite distant) object, the fifth lens group G5 and the sixth lens group G6 move toward the object along the optical axis by different amounts of movement.

The sixth lens group G6 consists of a positive meniscus lens L61 having a concave surface facing the object. The positive meniscus lens L61 has an image-side lens surface that is an aspherical surface.

The seventh lens group G7 consists of, in order from the object: a positive meniscus lens L71 having a concave surface facing the object; a biconcave negative lens L72; and a negative meniscus lens L73 having a concave surface facing the object. An image surface I is disposed on the image side of the seventh lens group G7. In this Example, the negative meniscus lens L73 of the seventh lens group G7 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like. The negative lens L72 has an object-side lens surface that is an aspherical surface.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive meniscus lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive lens L23, and the negative meniscus lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive meniscus lens L31, the positive lens L32, the cemented lens consisting of the negative meniscus lens L41 and the biconvex positive lens L42, the negative meniscus lens L51, the biconvex positive lens L52, the positive meniscus lens L61, the positive meniscus lens L71, the negative lens L72, and the negative meniscus lens L73 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 7 lists values of data on the optical system according to Seventh Example.

TABLE 7 [General Data] Zooming ratio = 2.743 W M T f 24.750 35.000 67.880 FNO 2.918 2.919 2.919 2ω 85.363 62.867 33.986 Y 21.600 21.600 21.600 TL 139.342 144.390 169.148 BF 11.701 15.449 28.388 fF −30.791 −34.682 −46.133 fR 28.627 28.934 30.359 [Lens Data] Surface Number R D nd νd θgF  1 234.38730 2.500 1.84666 23.80 0.6215  2 109.51800 5.200 1.75500 52.34 0.5476  3 389.68520 0.200  4 59.06270 5.700 1.77250 49.62 0.5518  5 135.36490  D5(Variable)  6* 218.44200 2.000 1.74389 49.53 0.5533  7 18.69570 9.658  8 −59.68560 1.300 1.77250 49.62 0.5518  9 59.68560 0.442 10 39.20990 6.400 1.72825 28.38 0.6069 11 −48.67310 1.933 12 −26.40650 1.300 1.61800 63.34 0.5411 13 −71.76120 D13(Variable) 14 ∞ 1.712 (Aperture Stop S)  15* 71.88760 2.500 1.69370 53.32 0.5475 16 127.64110 0.716 17 38.74920 5.900 1.59319 67.90 0.5440 18 −105.42740 D18(Variable) 19 67.02760 1.300 1.73800 32.33 0.5900 20 19.51260 9.700 1.49782 82.57 0.5386 21 −50.56090 D21(Variable) 22 −23.92370 1.200 1.72047 34.71 0.5834 23 −56.20810 0.200 24 103.17490 5.900 1.59349 67.00 0.5358 25 −33.01970 D25(Variable) 26 −70.62880 3.500 1.79189 45.04 0.5596  27* −38.21530 D27(Variable) 28 −44.77940 3.000 1.94595 17.98 0.6544 29 −32.36650 0.200  30* −90.76890 1.500 1.85207 40.15 0.5685 31 89.91740 7.847 32 −24.20670 1.400 1.65240 55.27 0.5607 33 −38.83480 BF [Aspherical Surface Data] 6th Surface κ = 1.000, A4 = 5.28E−06, A6 = −5.42E−09 A8 = 1.33E−11, A10 = −2.05E−14, A12 = 2.05E−17 15th Surface κ = 1.000, A4 = −4.56E−06, A6 = −1.40E−10 A8 = −8.81E−13, A10 = −8.43E−15, A12 = 0.00E+00 27th Surface κ = 1.000, A4 = 1.10E−05, A6 = −2.36E−08 A8 = 1.43E−10, A10 = −5.03E−13, A12 = 7.52E−16 30th Surface κ = 1.000, A4 = −2.11E−06, A6 = −2.12E−08 A8 = 3.23E−11, A10 = −8.72E−14, A12 = 0.00E+00 [Variable Distance Data on Zoom Photographing] W M T D5 1.780 11.383 30.246 D13 19.285 9.934 2.013 D18 9.167 6.537 1.493 D21 5.179 7.338 19.018 D25 2.679 3.818 2.616 D27 6.344 6.725 2.168 [Lens Group Data] Group First surface Focal length G1 1 119.124 G2 6 −22.126 G3 15 40.880 G4 19 115.687 G5 22 124.717 G6 26 100.365 G7 28 −47.354 [Conditional Expression Corresponding Value] <Negative meniscus lens L73(fLZ = −102.373)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.013 Conditional Expression(2)νdLZ = 55.27 Conditional Expression(3), (3-1)θgFLZ = 0.5607 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0118 Conditional Expression(5)|fLZ|/fR = 3.576 Conditional Expression(7)|fLZ|/f = 4.136 Conditional Expression(8)DLZ = 1.400

FIG. 14A shows various aberration graphs of the optical system according to Seventh Example upon focusing on infinity in the wide angle end state. FIG. 14B shows various aberration graphs of the optical system according to Seventh Example upon focusing on infinity in the intermediate focal length state. FIG. 14C shows various aberration graphs of the optical system according to Seventh Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Seventh Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Eighth Example

Eighth Example is described with reference to FIGS. 15 and 16A, 16B and 16C, and Table 8. FIG. 15 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Eighth Example of this embodiment. The optical system LS(8) according to Eighth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a negative refractive power; and a fifth lens group G5 having a positive refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to fifth lens groups G1 to G5 move in directions indicated by arrows in FIG. 15. The aperture stop S is disposed in the third lens group G3.

The first lens group G1 consists of, in order from the object: a cemented lens consisting of a negative meniscus lens L11 having a convex surface facing the object, and a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; a biconcave negative lens L22; a biconvex positive lens L23; and a negative meniscus lens L24 having a concave surface facing the object. Upon focusing from the infinity object to the short-distant (finite distant) object, the second lens group G2 moves toward the object along the optical axis. The negative meniscus lens L21 has an object-side lens surface that is an aspherical surface. The negative meniscus lens L24 has an image-side lens surface that is an aspherical surface.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a negative meniscus lens L32 having a convex surface facing the object, and a biconvex positive lens L33; and a biconvex positive lens L34. An aperture stop S is disposed between the positive lens L31 and the negative meniscus lens L32 (of the cemented lens) of the third lens group G3.

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a positive meniscus lens L41 having a concave surface facing the object, and a negative meniscus lens L42 having a concave surface facing the object; and a biconcave negative lens L43. In this Example, the negative lens L43 of the fourth lens group G4 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like.

The fifth lens group G5 consists of, in order from the object: a biconvex positive lens L51; and a cemented lens consisting of a biconvex positive lens L52, and a biconcave negative lens L53. An image surface I is disposed on the image side of the fifth lens group G5. The positive lens L51 has an object-side lens surface that is an aspherical surface.

In this Example, the cemented lens consisting of the negative meniscus lens L11 and the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive lens L23, the negative meniscus lens L24, and the positive lens L31 constitute the front group GF disposed closer to the object than the aperture stop S. The cemented lens consisting of the negative meniscus lens L32 and the positive lens L33, the positive lens L34, the cemented lens consisting of the positive meniscus lens L41 and the negative meniscus lens L42, the negative lens L43, the positive lens L51, and the cemented lens consisting of the positive lens L52 and the negative lens L53 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 8 lists values of data on the optical system according to Eighth Example.

TABLE 8 [General Data] Zooming ratio = 4.708 W M T f 24.720 49.985 116.383 FNO 4.070 4.067 4.075 2ω 86.259 43.985 19.680 Y 21.600 21.600 21.600 TL 147.198 161.190 192.200 BF 32.884 42.859 55.059 fF 110.031 −646.229 −317.953 fR 67.056 67.484 65.974 [Lens Data] Surface Number R D nd νd θgF  1 200.00000 1.200 1.84944 22.29 0.6222  2 112.14330 7.349 1.49782 82.57 0.5138  3 −312.82020 0.100  4 58.25030 5.717 1.59159 54.50 0.5508  5 133.86910  D5(Variable)  6* 68.14700 1.050 1.95375 32.33 0.5916  7 17.41650 6.493  8 −50.35820 1.200 1.66903 45.08 0.5674  9 35.82750 0.100 10 36.58470 6.379 1.84706 22.34 0.6220 11 −41.51350 0.788 12 −27.90490 1.200 1.61571 50.69 0.5574  13* −1318.72980 D13(Variable) 14 42.13090 3.781 1.62079 50.23 0.5583 15 −94.85060 0.100 16 ∞ 0.100 (Aperture Stop S) 17 39.33600 1.200 1.93546 24.49 0.6135 18 18.65160 5.400 1.49996 81.44 0.5151 19 −167.55480 0.100 20 47.06670 2.967 1.59687 53.64 0.5523 21 −353.88140 D21(Variable) 22 −35.39840 3.883 1.92286 20.88 0.6286 23 −18.10590 1.200 1.68303 40.83 0.5750 24 −151.76460 2.275 25 −61.36760 1.200 1.67769 52.63 0.5546 26 323.52730 D26(Variable)  27* 128.28980 5.951 1.50114 80.83 0.5161 28 −24.91200 0.100 29 72.70400 7.368 1.69764 43.43 0.5703 30 −24.43980 4.083 1.89451 29.27 0.5989 31 82.68200 BF [Aspherical Surface Data] 6th Surface κ = 1.000, A4 = −3.63E−06, A6 = −9.23E−09 A8 = 2.66E−11, A10 = −7.08E−14, A12 = 0.00E+00 13th Surface κ = 1.000, A4 = −1.30E−05, A6 = −9.67E−09 A8 = −4.06E−11, A10 = 0.00E+00, A12 = 0.00E+00 27th Surface κ = 1.000, A4 = −1.50E−05, A6 = 9.99E−09 A8 = −2.45E−11, A10 = 3.21E−14, A12 = 0.00E+00 [Variable Distance Data on Zoom Photographing] W M T D5 1.500 19.687 47.442 D13 24.608 10.433 1.500 D21 2.869 10.044 14.916 D26 14.054 6.884 2.000 [Lens Group Data] Group First surface Focal length G1 1 116.400 G2 6 −18.800 G3 14 27.200 G4 22 −46.400 G5 27 55.800 [Conditional Expression Corresponding Value] <Negative lens L43(fLZ = −76.021)> Conditional Expression (1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.021 Conditional Expression(2)νdLZ = 52.63 Conditional Expression(3), (3-1)θgFLZ = 0.5546 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0012 Conditional Expression(6)|fLZ|/fR = 1.134 Conditional Expression(7)|fLZ|/f = 3.075 Conditional Expression(8)DLZ = 1.200

FIG. 16A shows various aberration graphs of the optical system according to Eighth Example upon focusing on infinity in the wide angle end state. FIG. 16B shows various aberration graphs of the optical system according to Eighth Example upon focusing on infinity in the intermediate focal length state. FIG. 16C shows various aberration graphs of the optical system according to Eighth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Eighth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Ninth Example

Ninth Example is described with reference to FIGS. 17 and 18A, 18B and 18C, and Table 9. FIG. 17 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Ninth Example of this embodiment. The optical system LS(9) according to Ninth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a negative refractive power; a third lens group G3 having a positive refractive power; a fourth lens group G4 having a positive refractive power; a fifth lens group G5 having a negative refractive power; and a sixth lens group G6 having a negative refractive power. Upon zooming from the wide-angle end state (W) to the telephoto end state (T), the first to sixth lens groups G1 to G6 move in directions indicated by arrows in FIG. 17. The aperture stop S is disposed between the second lens group G2 and the third lens group G3.

The first lens group G1 consists of, in order from the object: a negative meniscus lens L11 having a convex surface facing the object; a biconvex positive lens L12; and a positive meniscus lens L13 having a convex surface facing the object.

The second lens group G2 consists of, in order from the object: a negative meniscus lens L21 having a convex surface facing the object; biconcave negative lens L22; a biconvex positive lens L23; and a negative meniscus lens L24 having a concave surface facing the object.

The third lens group G3 consists of, in order from the object: a biconvex positive lens L31; a cemented lens consisting of a negative meniscus lens L32 having a convex surface facing the object, and a biconvex positive lens L33; and a negative meniscus lens L34 having a concave surface facing the object. The aperture stop S is disposed adjacent to the object side of the positive lens L31, and moves with the third lens group G3 upon zooming. The cemented lens consisting of the negative meniscus lens L32 and the positive lens L33 of the third lens group G3 constitutes a vibration-proof lens group (partial group) that is movable in a direction perpendicular to the optical axis, and corrects variation in imaging position due to a camera shake and the like (image blur on the image surface I).

The fourth lens group G4 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L41, and a negative meniscus lens L42 having a concave surface facing the object; and a cemented lens consisting of a negative meniscus lens L43 having a convex surface facing the object, and a biconvex positive lens L44. The positive lens L44 has an image-side lens surface that is an aspherical surface.

The fifth lens group G5 consists of, in order from the object: a cemented lens consisting of a biconvex positive lens L51, and a biconcave negative lens L52. Upon focusing from the infinity object to the short-distant (finite distant) object, the fifth lens group G5 moves toward the image along the optical axis. The negative lens L52 has an image-side lens surface that is an aspherical surface.

The sixth lens group G6 consists of, in order from the object: a negative meniscus lens L61 having a concave surface facing the object; and a biconvex positive lens L62. An image surface I is disposed on the image side of the sixth lens group G6. In this Example, the negative meniscus lens L61 of the sixth lens group G6 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like. The negative meniscus lens L61 has an image-side lens surface that is an aspherical surface.

In this Example, the negative meniscus lens L11, the positive lens L12, the positive meniscus lens L13, the negative meniscus lens L21, the negative lens L22, the positive lens L23, and the negative meniscus lens L24 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L31, the cemented lens consisting of the negative meniscus lens L32 and the positive lens L33, the negative meniscus lens L34, the cemented lens consisting of the positive lens L41 and the negative meniscus lens L42, the cemented lens consisting of the negative meniscus lens L43 and the positive lens L44, the cemented lens consisting of the positive lens L51 and the negative lens L52, the negative meniscus lens L61, and the positive lens L62 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 9 lists values of data on the optical system according to Ninth Example.

TABLE 9 [General Data] Zooming ratio = 7.848 W M T f 24.720 50.000 194.001 FNO 4.120 5.578 7.747 2ω 85.978 44.803 12.176 Y 21.379 21.700 21.700 TL 133.622 151.172 196.635 BF 11.869 21.707 38.749 fF −22.437 −28.257 −22.437 fR 25.992 24.661 25.992 [Lens Data] Surface Number R D nd νd θgF  1 185.39670 1.700 1.90366 31.27 0.5948  2 76.46580 0.861  3 79.26480 6.196 1.59319 67.90 0.5440  4 −565.11920 0.100  5 63.45420 5.498 1.59319 67.90 0.5440  6 434.75200  D6(Variable)  7 203.01440 1.100 1.90265 35.72 0.5804  8 19.06950 5.142  9 −53.01680 1.000 1.75500 52.33 0.5475 10 58.98300 0.511 11 37.16720 3.158 1.92286 20.88 0.6390 12 −70.22260 0.694 13 −33.57890 0.903 1.81600 46.59 0.5567 14 −1345.01350 D14(Variable) 15 ∞ 2.000 (Aperture Stop S) 16 40.44850 2.345 1.90265 35.72 0.5804 17 −316.98760 0.605 18 35.70840 1.000 2.00100 29.12 0.5996 19 20.49290 3.549 1.57957 53.74 0.5519 20 −74.86330 1.410 21 −37.16210 1.047 1.95375 32.33 0.5905 22 −418.77410 D22(Variable) 23 37.79500 4.737 1.83481 42.73 0.5648 24 −37.79500 1.004 1.90366 31.27 0.5948 25 −353.80920 0.100 26 31.05870 3.102 1.95375 32.33 0.5905 27 15.35540 8.795 1.49710 81.49 0.5377  28* −42.90350 D28(Variable) 29 474.24510 3.208 1.84666 23.80 0.6215 30 −34.68120 1.002 1.85135 40.13 0.5685  31* 31.38060 D31(Variable) 32 −17.69750 1.400 1.68348 54.80 0.5501  33* −23.26090 0.100 34 1014.6406  2.7385 1.68376 37.57 0.5782 35 −99.7136 BF [Aspherical Surface Data] 28th Surface κ = 1.000, A4 = 2.96E−05, A6 = −1.43E−07 A8 = 1.92E−09, A10 = −1.38E−11, A12 = 3.3122E−14 31st Surface κ = 1.000, A4 = −5.38E−06, A6 = 1.47E−07 A8 = −2.09E−09, A10 = 1.45E−11, A12 = −3.5486E−14 33rd Surface κ = 1.000, A4 = −2.59E−06, A6 = −1.89E−08 A8 = 8.54E−11, A10 = −2.37E−13, A12 = 0.00E+00 [Variable Distance Data on Zoom Photographing] W M T D6 1.982 18.089 56.429 D14 19.455 11.059 1.140 D22 13.005 6.692 1.483 D28 4.951 4.074 1.900 D31 9.993 17.182 24.566 [Lens Group Data] Group First surface Focal length G1 1 103.302 G2 7 −16.985 G3 15 48.485 G4 23 29.299 G5 29 −39.415 G6 32 −2329.811 [Conditional Expression Corresponding Value] <Negative meniscus lens L61(fLZ = −120.581)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)gFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(6)|fLZ|/fR = 4.639 Conditional Expression(7)|fLZ|/f = 4.878 Conditional Expression(8)DLZ = 1.400

FIG. 18A shows various aberration graphs of the optical system according to Ninth Example upon focusing on infinity in the wide angle end state. FIG. 18B shows various aberration graphs of the optical system according to Ninth Example upon focusing on infinity in the intermediate focal length state. FIG. 18C shows various aberration graphs of the optical system according to Ninth Example upon focusing on infinity in the telephoto end state. The various aberration graphs show that the optical system according to Ninth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

Tenth Example

Tenth Example is described with reference to FIGS. 19 and 20A, 20B and 20C, and Table 10. FIG. 19 is a diagram showing a lens configuration of an optical system in a state upon focusing on infinity according to Tenth Example of this embodiment. The optical system LS(10) according to Tenth Example consists of, in order from the object: a first lens group G1 having a positive refractive power; a second lens group G2 having a positive refractive power; and a third lens group G3 having a negative refractive power. Upon focusing from the infinity object to the short-distant (finite distant) object, the first lens group G1 and the second lens group G2 move toward the object along the optical axis by different amounts of movement. The aperture stop S is disposed between the first lens group G1 and the second lens group G2.

The first lens group G1 consists of, in order from the object: a biconcave negative lens L11; a biconvex positive lens L12; a cemented lens consisting of a biconvex positive lens L13 and a biconcave negative lens L14; and a negative meniscus lens L15 having a convex surface facing the object. The aperture stop S is disposed adjacent to the image side of the negative meniscus lens L15, and moves with the first lens group G1 upon focusing. The negative lens L11 has an image-side lens surface that is an aspherical surface.

The second lens group G2 consists of, in order from the object: a biconvex positive lens L21; and a negative meniscus lens L22 having a convex surface facing the object.

The third lens group G3 consists of, in order from the object: a positive meniscus lens L31 having a convex surface facing the object; a negative meniscus lens L32 having a concave surface facing the object; and a biconvex positive lens L33. An image surface I is disposed on the image side of the third lens group G3. In this Example, the negative meniscus lens L32 of the third lens group G3 corresponds to a specified lens that satisfies the conditional expressions (1) to (4) and the like. The positive meniscus lens L31 has an image-side lens surface that is an aspherical surface. A cover glass CV is disposed between the third lens group G3 and the image surface I.

In this Example, the negative lens L11, the positive lens L12, the cemented lens consisting of the positive lens L13 and the negative lens L14, and the negative lens L15 constitute the front group GF disposed closer to the object than the aperture stop S. The positive lens L21, the negative meniscus lens L22, the positive meniscus lens L31, the negative meniscus lens L32, and the positive lens L33 constitute the rear group GR disposed closer to the image than the aperture stop S.

The following Table 10 lists values of data on the optical system according to Tenth Example.

TABLE 10 [General Data] f 58.203 FNO 2.825 2ω 40.539 Y 21.700 TL 71.506 BF 0.100 fF 193.264 fR 41.152 [Lens Data] Surface Number R D nd νd θgF  1 −63.99090 1.200 1.73077 40.51 0.5727  2* 71.71180 1.000  3 42.93270 4.064 1.95375 32.33 0.5905  4 −51.23440 1.082  5 49.88300 4.042 1.59319 67.90 0.5440  6 −30.98750 1.200 1.73800 32.26 0.5899  7 45.45620 0.200  8 31.62520 1.200 1.80518 25.45 0.6157  9 22.75910 6.464 10 ∞ D10(Variable) (Aperture Stop S) 11 54.06210 3.455 1.59349 67.00 0.5358 12 −32.76480 0.200 13 31.23990 1.200 1.67300 38.15 0.5754 14 22.30120 D14(Variable) 15 43.39570 1.373 1.51680 64.13 0.5357  16* 43.24690 17.859  17 −17.25440 1.200 1.68348 54.80 0.5501 18 −176.84520 0.200 19 159.39470 4.819 1.95375 32.33 0.5905 20 83.44720 12.310  21 ∞ 1.600 1.51680 64.13 0.5357 22 ∞ BF [Aspherical Surface Data] 2nd Surface κ = 1.000, A4 = 1.39250E−05, A6 = 3.07014E−09 A8 = −6.46165E−12, A10 = 0.00000E+00, A12 = 0.00000E+00 16th Surface κ = 1.000, A4 = −1.14801E−05, A6 = −6.50435E−09 A8 = −1.06124E−10, A10 = 0.00000E+00, A12 = 0.00000E+00 [Variable Distance Data on Short-Distance Photographing] Upon Upon focusing on Upon focusing on focusing an intermediate a short-distance on infinity distance object object f = 58.203 β = −0.500 β = −1.000 D10 5.331 5.445 5.684 D14 1.412 18.266 35.060 [Lens Group Data] Group First surface Focal length G1 1 193.264 G2 11 46.831 G3 15 −60.650 [Conditional Expression Corresponding Value] <Negative meniscus lens L32(fLZ = −28.060)> Conditional Expression(1) ndLZ − (2.015 − 0.0068 × νdLZ) = 0.041 Conditional Expression(2)νdLZ = 54.80 Conditional Expression(3), (3-1)θgFLZ = 0.5501 Conditional Expression(4), (4-1) θgFLZ − (0.6418 − 0.00168 × νdLZ) = 0.0004 Conditional Expression(6)|fLZ|/fR = 0.682 Conditional Expression(7)|fLZ|/f = 0.482 Conditional Expression(8)DLZ = 1.200

FIG. 20A shows various aberration graphs of the optical system according to Tenth Example upon focusing on infinity. FIG. 20B shows various aberration graphs of the optical system according to Tenth Example upon focusing on an intermediate distant object. FIG. 20C shows various aberration graphs of the optical system according to Tenth Example upon focusing on a short-distant (very short distance) object. The various aberration graphs show that the optical system according to Tenth Example has favorably corrected various aberrations, and exerts excellent imaging performance.

According to each Example, the optical system where for correction of chromatic aberrations, in addition to primary achromatization, the secondary spectrum is favorably corrected can be achieved.

Here, Examples described above show specific examples of the invention of the present application. The invention of the present application is not limited to these Examples.

Note that the following content can be adopted in a range without impairing the optical performance of the optical system of this embodiment.

The focusing lens group is assumed to indicate a portion that includes at least one lens separated by air distances changing upon focusing. That is, a focusing lens group may be adopted that moves a single or multiple lens groups, or a partial lens group in the optical axis direction to achieve focusing from the infinity object to the short-distant object. The focusing lens group is also applicable to autofocusing, and is suitable also for motor drive for autofocusing (using an ultrasonic motor).

In Eighth to Eleventh Examples, the configurations having the vibration-proof function are described. However, the present application is not limited thereto, and may adopt a configuration having no vibration-proof function. The other Examples having no vibration-proof function may have a configuration having the vibration-proof function.

The lens surface may be made of a spherical surface or a planar surface, or an aspherical surface. A case where the lens surface is a spherical surface or a planar surface is preferable because lens processing, and assembling and adjustment are facilitated, and the optical performance degradation due to errors caused by processing and assembling and adjustment can be prevented. Furthermore, it is preferable because the degradation in representation performance even with the image surface being misaligned is small.

In a case where the lens surface is an aspherical surface, the aspherical surface may be any of an aspherical surface made by a grinding process, a glass mold aspherical surface made by forming glass into an aspherical shape with a mold, and a composite type aspherical surface made by forming a resin on a surface of glass into an aspherical shape. The lens surface may be a diffractive surface. The lens may be a gradient-index lens (GRIN lens), or a plastic lens.

An antireflection film having a high transmissivity in a wide wavelength region may be applied onto each lens surface in order to reduce flares and ghosts and achieve optical performances having a high contrast. Accordingly, flares and ghosts can be reduced, and high optical performances having a high contrast can be achieved.

EXPLANATION OF NUMERALS AND CHARACTERS G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G5 Fifth lens group I Image surface S Aperture stop 

1. An optical system comprising a lens, the lens satisfying the following conditional expressions: −0.010<ndLZ−(2.015−0.0068×νdLZ), 50.00<νdLZ<65.00, 0.545<θgFLZ, −0.010<θgFLZ−(0.6418−0.00168×νdLZ) where ndLZ: a refractive index of the lens for d-line, νdLZ: an Abbe number of the lens with reference to d-line, and θgFLZ: a partial dispersion ratio of the lens, defined by a following expression when a refractive index of the lens for g-line is ngLZ, a refractive index of the lens for F-line is nFLZ, and a refractive index of the lens for C-line is nCLZ: θgFLZ=(ngLZ−nFLZ)/(nFLZ−nCLZ).
 2. The optical system according to claim 1, consisting of: an aperture stop; a front group disposed closer to an object than the aperture stop; and a rear group disposed closer to an image than the aperture stop, wherein the front group includes the lens and satisfies the following conditional expression: −10.00<|fLZ|/fF<10.00 where fLZ: a focal length of the lens, and fF: a focal length of the front group; in a case where the optical system is a zoom optical system, the focal length of the front group in the wide angle end state.
 3. The optical system according to claim 1, consisting of: an aperture stop; a front group disposed closer to an object than the aperture stop; and a rear group disposed closer to an image than the aperture stop, wherein the rear group includes the lens and satisfies the following conditional expression: −10.00<|fLZ|/fR<10.00 where fLZ: a focal length of the lens, and fR: a focal length of the rear group; in a case where the optical system is a zoom optical system, the focal length of the rear group in a wide angle end state.
 4. The optical system according to claim 1, wherein the lens satisfies the following conditional expression: 0.10<|fLZ|/f<15.00 where fLZ: a focal length of the lens, and f: a focal length of the optical system; in a case where the optical system is a zoom optical system, the focal length of the optical system in a wide angle end state.
 5. The optical system according to claim 1, wherein the lens satisfies the following conditional expression: 0.555<θgFLZ.
 6. The optical system according to claim 1, wherein the lens satisfies the following conditional expression: 0.010<θgFLZ−(0.6418−0.00168×νdLZ).
 7. The optical system according to claim 1, wherein the lens satisfies the following conditional expression: DLZ>0.400 [mm] where DLZ: a thickness of the lens on an optical axis.
 8. The optical system according to claim 1, wherein the lens is a single lens, or one lens of two lenses of a cemented lens consisting of the two lenses cemented to each other.
 9. The optical system according to claim 1, wherein at least one lens surface of an object-side lens surface and an image-side lens surface of the lens is in contact with air.
 10. The optical system according to claim 1, wherein the lens is a glass lens.
 11. An optical apparatus comprising the optical system according to claim
 1. 12. A method for manufacturing an optical system, the method comprises a step of arranging at least one lens in a lens barrel, the lens satisfying the following conditional expressions: −0.010<ndLZ−(2.015−0.0068×νdLZ), 50.00<νdLZ<65.00, 0.545<θgFLZ, −0.010<θgFLZ−(0.6418−0.00168×νdLZ) where ndLZ: a refractive index of the lens for d-line, νdLZ: an Abbe number of the lens with reference to d-line, and θgFLZ: a partial dispersion ratio of the lens, defined by a following expression when a refractive index of the lens for g-line is ngLZ, a refractive index of the lens for F-line is nFLZ, and a refractive index of the lens for C-line is nCLZ: θgFLZ=(ngLZ−nFLZ)/(nFLZ−nCLZ). 